This invention relates to the field of mechanical connectors, and in particular to a connector that is suitable for coupling large objects, such as spacecraft to launch vehicles.
Transport systems, such as rockets that transport satellites into space, vessels that transport submerged sections of ocean structures such as oil platforms, and the like, require a means for securely fastening different items together for transport, and reliably and easily unfastening the items for deployment. Multi-stage rockets also require a means for fastening the stages together, and reliably unfastening the stages as each stage is spent. In other situations, such as aircraft carrier based aircraft, the items are transported or stored in a disassembled state and require a means for rapidly fastening the items for deployment, and reliably and easily unfastening the items for subsequent storage or transport.
A variety of devices have been developed to secure two items together while also allowing the items to be separated quickly and reliably. In the aerospace industry, the common connection devices include bolts and bands that can be severed. Bolts are used to fasten the two items together, and an explosive charge is typically used to sever the bolts at the proper time, thereby unfastening the two items. Depending upon the application, ancillary devices such as springs may be used to urge the two items apart when the bolts are severed. To assure a reliable separation, the number of bolts used to fasten the two items is kept to a minimum; this results in load points at the bolts far in excess of the load imposed by a distributed fastening system.
Belt structures are commonly used to provide for a distributed load. A belt structure that is commonly employed to fasten items together is a “V-band”, typified by U.S. Pat. No. 4,715,565, “CLAMPING CONNECTION ASSEMBLY FOR SPACECRAFT”, issued 29 Dec. 1987 to Alois Wittmann, and incorporated by reference herein. The V-band includes a tension belt for securing a plurality of retainers against camming surfaces on flange members on separable spacecraft component parts. A typical V-band embodiment consists of an upper ring attached to the payload, a lower ring attached to the launch vehicle, and a clampband that is circumferentially tensioned to the flanges of the upper and lower rings. The clampband is conventionally tensioned by bolts, and explosive bolt cutters are used to sever the bolts to release the tension. Because of the high tension requirements, the combined weight of the belt, clamps, and ancillary required devices is substantial (as much as 45 pounds for a 38 inch diameter V-band structure). The high tension requirements of V-bands often require specialized tools and instruments to tension the band. The high tension and high release shock effects also limits the reliable life of the components, thereby limiting the amount of testing that can be applied to the components that are actually flown.
Another structure that is commonly used to provide for an easily separable connection is an explosive frangible joint, as typified by U.S. Pat. Nos. 4,685,376 and 5,390,606. The explosive frangible joint is commonly used in lieu of the aforementioned V-band for large diameter structures, typically greater than 30 inches. An explosive detonating cord is placed within a contained space that forms the frangible joint between the two items. Separation is achieved by detonating the cord within the contained space, forcing a rapid crack propagation through the frangible joint. Although the weight of an explosive frangible joint is less than that of an equivalent sized V-band, it is still substantial (as much as 17 pounds for a 38 inch diameter joint). The destructive nature of this separation system precludes testing of the joints that are actually flown. Many launched vehicles have been lost due to a failure in the explosive separation system, and many satellites have been damaged due to explosive shock.
Each of the aforementioned separation connectors also imparts a substantial shock to the connected items upon separation, and the explosive nature of the devices used for separation introduce a risk of personal injury, particularly during pre-launch assembly and testing. Because of the shock effects, such separation connectors are not commonly used on items that are routinely disassembled for storage or transport, and explosive joints are not commonly used on fragile devices, such as spacecraft/satellites.
A lighter, non-explosive, and reusable coupling system is disclosed in U.S. Pat. No. 6,227,493, “REUSABLE, SEPARABLE, STRUCTURAL CONNECTOR ASSEMBLY”, and its continuation-in-part, U.S. Pat. No. 6,343,770, issued 8 May 2001 and 5 Feb. 2002, respectively, to Walter Holemans; each of which are incorporated by reference herein. This reusable coupling system employs a plurality of leaves with leaf lips that are secured within a mating surface by a band. The leaves and mating surface are designed such that the tension required on the band is significantly less than the tension required on a V-band. When the band is detensioned, springs urge the leaves away from the mating surface, thereby allowing for the separation of the connected items. The leaf lips can be configured to face toward an interior of a perimeter, and the band is contracted to hold the lips against an interior mating surface; or, the leaf lips can be configured to face toward an exterior of a perimeter, and the band is expanded to hold the lips against an exterior mating surface.
Although this coupling system overcomes most of the limitations of former systems, and particularly the limitations of explosive systems, it relies upon exerting a radial force, either outward or inward, about a substantially continuous perimeter of leaf lips. Additional means, such as spring elements, are also provided to assure that the leaf lips are disengaged from the mating surface.
It is an object of this invention to provide a non-explosive and reusable coupling system that provides for substantially bistable operation. It is a further object of this invention to provide a non-explosive and reusable coupling system that integrates both the coupling and decoupling means. It is a further object of this invention to provide a non-explosive and reusable coupling system that does not require exerting a radial force. It is a further object of this invention to provide a non-explosive and reusable coupling system that does not require a continuous perimeter of engaging elements.
These objects, and others, are achieved by a coupling system that includes latching elements on a first structure that are configured to securely engage corresponding bearings on a second structure. When engaged, or when disengaged, the system is in a stable state, requiring no active force by the controlling system to maintain the system in each state. The coupling system includes a pair of coupling elements, one of which includes a plurality of latching elements, and the other of which includes a plurality of corresponding bearings. A lateral member provides simultaneous rotation of the plurality of latching elements to engage, or disengage, the latching elements from the bearings. Preferably, each latching element is coupled to the lateral member via a pinion that provides a mechanical advantage that substantially reduces the force required on the lateral member to effect the coupling or decoupling. Also preferably, the elements are formed from extruded aluminum forms, thereby providing for a relatively inexpensive and lightweight configuration.
Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions. The drawings are included for illustrative purposes, are not drawn to scale, and are not intended to limit the scope of the invention.